NHTSA Proposes Cyan Lights for Autonomous Vehicles

Federal regulators have proposed a rule that would establish a specific blue-green light to indicate when an automated driving system is in control of a vehicle. The National Highway Traffic Safety Administration (NHTSA) released proposed modifications to Federal Motor Vehicle Safety Standard (FMVSS) No. 108, which outlines regulations for vehicle lighting. This proposal aims to create a national standard for how self-driving cars communicate their status to other road users and law enforcement, while also simplifying certain existing requirements for vehicles that do not have a human driver.

The proposed rule would require vehicles equipped with an automated driving system to be fitted with cyan-colored marker lamps. The color cyan was chosen because the automotive industry already uses other colors for specific functions: red for brake lights, amber for turn signals, white for headlights, and flashing blue and red for emergency vehicles. Regulators believe cyan can fill a visual gap without causing confusion. The proposal also establishes national standards for the color, brightness, and location of these lights. This would create a uniform setup for manufacturers who choose to install them, including autonomous vehicle operators like Waymo, Nuro, and Zoox, as well as automakers like GM and Mercedes.

The proposal to standardize the color cyan for autonomous vehicles has precedent in the industry. Mercedes-Benz previously received state-level approval for turquoise lights on its Level 3 Drive Pilot systems. Although the company has since discontinued that feature, the idea is being revived at the federal level to create a consistent visual indicator for all autonomous vehicles. The move is part of a broader effort by the Department of Transportation to streamline the deployment of autonomous vehicles. The government aims to simplify the process for automakers to build vehicles without traditional controls like steering wheels and pedals, which are designed for human-operated cars.

In addition to establishing new standards for autonomous vehicles, the proposed rule would also remove several existing requirements that are not applicable to a car without a human driver. Current regulations mandate physical hazard switches, manual beam shifters, and turn levers inside a vehicle. The proposal would eliminate these requirements. It also proposes to update the 12.8-volt testing standard to accommodate modern LED lighting architectures and is considering removing rules that dictate the vertical position of high-beam and low-beam lights.

While regulators are working to streamline rules for autonomous vehicles, they are also still enforcing current regulations. Last month, NHTSA opened an audit query into the Tesla Cybercab to examine the process and technical data Tesla used to certify the vehicle. The inquiry focuses on the absence of certain design features, including sideview mirrors, pedals, and a steering wheel, all of which are required under FMVSS.

The proposed changes to FMVSS No. 108 are currently open for public comment. Regulators will review the feedback before deciding whether to finalize the proposed rule.